iptables
Linux Firewall Rule Visualizer
1Packet Flow Diagram
2Table & Chain Reference
The filter table is the default table for packet filtering — allowing or denying packets. Most firewall rules go here.
INPUT
FORWARD
OUTPUT
The nat table is consulted for packets that create a new connection. Used for Network Address Translation (SNAT, DNAT, MASQUERADE).
PREROUTING
OUTPUT
POSTROUTING
The mangle table is used for specialized packet alteration — modifying TTL, TOS, MARK fields, etc. Applied to all 5 chains.
PREROUTING
INPUT
FORWARD
OUTPUT
POSTROUTING
The raw table has the highest priority and is mainly used to configure exemptions from connection tracking (NOTRACK). Applied before connection tracking.
PREROUTING
OUTPUT
3Rule Builder filter table
iptables command
iptables -A INPUT -j ACCEPT
nftables equivalent
nft add rule ip filter input accept
Current Ruleset
No rules yet — build one above or load a template.
4Common Rule Templates
5Default Chain Policies
The default policy is the action taken when a packet reaches the end of a chain without matching any rule. Toggle to see the effect.